"The hunter killed the lion." >"The lion was killed by the hunter."
"I will repair this car later." > "This car will be repaired later."
"Someone has cleaned the windows." > "The windows have
been cleaned by someone"
- Het stukje "by ..." is optioneel en hoeft er niet per se achter.
- Er komt altijd een vorm van "be" bij (was/were/been/being/...)